The municipality of Miercurea-Ciuc is situated in the Eastern part of Transylvania, in the central zone of the Ciucurilor Depression being rounded by the volcanical mountain range of the Harghita and Ciuc Mountains at the crossing of the roads which pass through the Carpathian Passes of Vlăhita (Tolvajos) and Ghimes.
Miercurea-Ciuc was founded in the 16th century near by existing localities as: Sumuleu (1333), TopliTa-Ciuc and Jigodin (the XII-XIIIth century) villages - with which it has since merged - in the flood area of the Olt river where market (peasant fairs) was held on Wednesdays (Hungarian - szerda).
The first known authentic document which certified this town as "a plain town" is a letter of Queen Izabella, mother of János Zsigmond, Prince of Transylvania, dated back from August, 5th, 1558, in which the inhabitants of the town were exempted from the taxes, but not from the ones to the Ottoman Empire.
At Sumuleu, in 1630, there was a Franciscan gymnasium, and in 1676 there was a printing shop of Franciscan monk Johannes Kájoni.

The parish church was built in 1758
The building of the fortress was decisive in the development of the settlement.
Ferenc Mikó of Hidveg (1585-1635), who was Gábor Bethlen's relative and confidant, and Chief Captain of Csik, Gyergyo, and Kaszon Chairs (traditional names for the Székely counties), built the castle with four bastions on the corners, a regular rectangular ground plan and a sketch in the style of the most beautiful Italian Renaissance sketches from the 1620-1635 period.
Its 'Golden Bastion' was mentioned by sources in 1654.
The fortress was burnt up by the Tartars in 1661, than fortified in 1714 by the Austrian garrison troops with an external defense ring consisting mainly of ramparts.
The first Székely Infantry Regiment was stationed in it from 1764 to 1884.
In 1849 as the commander-in-chief of the Székely revolutionary troops Gál Sándor had his headquarters in the Mikó Castle in Miercurea-Ciuc (Csíkszereda).

Its south-western bastion housed a chapel which functioned as a branch of Somlyó till 1751.
The Gothic windows of the chapel, provided that they were not built as a result of the Romantic renewal, are a good example of the survival of the Gothic forms that reappeared every now and then during the 17th century.

In 1849 revolutionist poet Petőfi Sándor paid a visit here and in the letter written to his wife, Julia, he mentioned: "The environs of Miercurea-Ciuc and Târgu-Secuiesc are wonderful".

Another important cultural establishment in Miercurea-Ciuc (Csíkszereda) is the Márton Áron Grammar School, which is proud of its traditions, celebrated its 300th anniversary in 1968.

The history of Miercurea-Ciuc (Csíkszereda) has been plagued with devastating raids by the Tartars, Turks, and Habsburg troops, only to be interrupted by peace periods when local high-noble tyrants ruled the land with and iron fist.
In 1717-1719, a very serious black pox epidemic killed two-thirds of the population of the town.
During the Hungarian Liberation Fight of 1848, patriotic newspapers, such as the Hadi Lap and the Csíki Gyutacs were printed in Miercurea-Ciuc (Csíkszereda).

Miercurea-Ciuc (Csíkszereda), with a population of 50,000, today is an important industrial town and continues to be the cultural and ethnic center of the Hungarian Székelys in the Székely-land.
These wonderful environs were put into account along the time being settled up many spas which use the table waters, mofettes, mountain picturesque landscape from here.

The traveler who arrives in Miercurea-Ciuc has good facilities of accommodation and meals in the "Bradul" Hotel (two stars) with 198 places in single and double bedded rooms, restaurant, bar, bathroom and TV set in each room. The hotel is situated in downtown.

The mountain lowers are able to choose the "Ozon" Hotel which is situated in the wonderful landscape of the Harghita Mountains near by the Harghita Băi Spa at 1504 m above sea level.
This hotel has single, double, three and four bedded fooms with bath, conference hall, restaurant, bar and sauna.